The present disclosure relates to a circulation system for mixing ink jet ink and in particular to a circulation system for mixing pigmented ink jet ink.
Ink jet printing is a well-known technique by which printing is accomplished without contact between the printing device and the substrate on which the printed characters are deposited. Briefly described, ink jet printing involves the technique of projecting a stream of ink droplets to a surface and controlling the direction of the stream so that the droplets are caused to form the desired printed image on that surface. This technique of noncontact printing is well suited for application of characters onto a variety of surfaces including porous and non-porous surfaces.
Pigmented ink, which includes insoluble pigment particles, may be used in ink jet printing. Although it has a number of desirable characteristics, pigmented ink also has a significant drawback. The pigment particles tend to agglomerate and settle at the bottom surface of the ink supply container, causing nozzle clogging and disruption in printing, as well as a decrease in print contrast. The nozzles typically have a diameter around about 2.5 to 3.0 thousandths of an inch, so agglomerated particles have a high tendency to clog the nozzles.